Radiant space heater

ABSTRACT

A radiant space heater includes separate and functionally distinct module units for (a) supporting a burner, (b) reversing the flow of combustion gases, and (c) supporting a tube end for discharge into a chimney, combustion tubes connecting them in serial order and two side frames which support the module units and which are themselves held in spaced relationship by the module units.

United States Patent 1191 Related US. Application Data Continuation-in-part of Ser. No. 281,743, Aug. 18, 1972, abandoned.

US. Cl. 126/91 A, 248/68 CB, 285/137 R,

References Cited I UNITED STATES PATENTS Liningeret al 126/110 R Schlosser Sept. 3, 1974 RADIANT SPACE HEATER 1,126,873 2/1915 Sample et a1. 126/116 R 2,270,824 1/1942 Meyerhoefer 126 110 B [76] lnvemorschlosser 29 Broad 2,504,315 4/1950 Fuerfile 126 110 R Hatfield, 19440 2,603,208 7 1952 Beauchamp 126/116 R 3,152,817 10/1964 Watson et al... 285/424 [22] June 1973 3,181,525 5 1965 McKann 126/94 [21] Appl. No.1 372,076 3,327,945 6/1967 Pfister 285/424 Primary Examiner-William E. Wayner Assistant Examiner-William E. Tapolcai, Jr.

57 ABSTRACT A radiant space heater includes separate and functionally distinct module units for (a) supporting a burner,

ytwo side frames which support the module units and which are themselves held in spaced relationship by the module units.

- 12 Claims, 15 Drawing Figures PATENTEUSEP 31924 SHEHIOF4 FIG. 4

FIG. 3

PATENTED 3,832,991

SHEET 20$ 4 PATENTED SEP 3574 SHEET 3!)? 4 FIG'I FIG.9

FIGS

RADIANT SPACE HEATER This application is a continuation-in-part of my parent application filed on Aug. 18, 1972 having US. Pat. Ser. No. 281,743, now abandoned.

This invention relates to space heaters and particularly to a self-fired heater which dissipates a major portion of the heat by radiation. Space heaters of this type are generally supported well above head level and include radiator fins or reflector vanes to direct radiant heat downwardly.

Although those prior, self-contained burner and radiating tube heatersserve to adequately deliver heat to the ambient space, they all have complicated structures. This not only makes it difficult and time consuming to assemble them initially, but even more time is required to take them apart to replace a damaged part. As the entire heater is subjected to an extremely high temperature due to the direct contact of the flame and hot combustion gases with the major structural parts, these parts are subject to unusual erosion and may burn through. The replacement of such damaged parts in the prior art space heaters has been quite difficult. In some instances, an entire complex casing structure would have to be replaced if only a small portion of its wall had become burned through.

In accordance with the present invention, the completed structure is made up of individual units which are each of fairly simple structure and which are readily assembled to form the composite heater. These advantages are achieved by making use of modular elements or units which have individualized functions. For instance, a key modular unit serves to reverse the flow of the hot combustion gases and direct it from one tube into the tube next above. These key, reverse flow modules are retained in assembled relation in a simplified manner, as will be explained and they possess the important feature that they can individually be replaced when the need arises. This facility of replacement is true of the other structural units of the complete heater, as will be made clear by the following description and drawings.

In the drawings:

FIG. 1 is a side elevational view of the heater with the forward reflectors removed to show the structure behind them,

FIG. 2 is a sectional view on the line 22 of FIG. 1,

FIG. 3 is an elevational view of the right hand end of FIG. I, a portion of the shield plate being broken away to show the structure behind it,

FIG. 4 is an enlarged, fragmentary, sectional view of the burner receiving module with the associated combustion tube displaced,

FIG. 5 is a perspective view of one of the two side frames, portions being broken away to show the structure on an enlargedscale,

FIG. 6'is a perspective view of one of the reverse-flow FIG. 10 is a front elevational view similar to FIG. 1 but showing modifications of the right hand end of FIG. 1, the reflector vanes being omitted,

FIG. 11 is a vertical sectional view through the axes of the combustion tubes of FIG. 10,

FIG. 12 is an enlarged view of the lower right hand portion of FIG. 11 to show the details,

FIG. 13 is a side elevational view of FIG. 12 with the heat shield omitted,

FIG. 14 is a front elevational view of the apertured plate of FIG. 10 for holding the reflectors,

FIG. 15 is a top end view of FIG. 14.

As the reverse-flow module unit 10, shown in detail in FIGS. 6 and 7, is a key element of the structure, it will be described first. It includes two parallel, laterally spaced side plates 11 and'12 and a connecting face plate 13. As shown, these plates are portions of a single sheet of metal which is bent to this U-shaped configuration. However, the plates 1 1, l2, and 13 can be individual plates which are welded or otherwise held together to form this shape and for convenience they will be referred to as plates. It will be noted that the face plate 13 is oblong and that the side plates 11 and 12 are on its long sides.

This face plate 13 has two holes therein, spaced along its length. At hole 14 and concentric therewith is an internal cylindrical ring 16 and at hole 15 and concentric therewith is an external cylindrical ring 17. Fitting between the side plates ll and 12 and also abutting the front plate 13, is a curved, deflecting plate 18. This deflecting plate preferably is hemi-cylindrical in curvature but as it serves to reverse the flow of the combus-,

tion gases, it is apparent that it may haveany suitable, general curvature.

The curved deflecting plate 18 is welded at all its edges to plates l1, l2, and 13 or is otherwise affixed to them so that a leak proof seal is established. The rings 16 and 17 are welded around their peripheries to the face plate 13. Welding is preferably utilized as the several plates are intended ,to be of heavy guage thickness, but it is apparent that any mechanical attachment means may be utilized. For instance, if a light duty heater is being made, the several plates and the rings may be held together by flanging the plates and rings and holding them together by rivets, sheet metal screws, or bolts and nuts. Or, the rings 16 and 17 may simply be pressed out from the face plate 13.

The internally located ring 16 has an internal diameter such that it will snugly receive therein a combustion tube 21. The externally located ring 17 has an external diameter such that a combustion tube 22 will firmly fit thereover and to retain it in place, sheet metal screws 24, or alternative attachment may be applied. The tube 21. is free to move slightly back or forth within ring 16 to allow for heat expansion and contraction and, to avoid binding, it is preferable that this end of the tube have longitudinal crimps or flutings, shown at 25.

In, the illustrated heater, there are four vertically spaced tubes, 20, 21, 22, and 23, but there may be fewer or more of them. A large capacity burner may make it desirable to use five or even six tubes to extract most of the heat before it escapes to the flue. Or, a

small capacity burner may make two or three tubes sufficient to obtain an efficient utilization of the heat from the burner.

In FIGS. I to 9, tubes 21, 22, and 23 are identical and the reverse-flow module units 10, 10a, and 10b are of identical construction. This duplication is an important feature as the initial assembly of the heater requires a minimum number of stock parts and for replacement purposes the same stock module will fit in either of the three places.

The lowermost tube slidably fits at one end in the reverse-flow module unit 10a and its other end is attached to a burner receiving module unit 26 best shown in FIG. 9. This unit consists of a plate 27 having a central opening 28 therethrough and a ring 29 affixed thereto as by welding, pressing outwardly of the plate material, etc. The ring 29 is of a size to tightly receive the adjacent end of tube 20 and to hold it in place the sheet metal screws 30, or alternative attachment means, are utilized. It will be observed that the tube 20 is longer than tubes 21, 22, and 23 by an amount equal to the depth of the reverse-flow module units 10. This plate 27 and its attached ring 29 is approximately half of end plate 13 to which ring 17 is affixed.

The topmost tube 23 is attached at one end to the upper flow module unit 10b and its other end slidably fits within the discharge module unit 31 best shown in H6. 8. This unit 31 is comparable to half of the reverse-flow units 10 in the sense that it causes a onefourth turn in the flow of the combustion gases so as to direct them upwardly into a chimney (not shown). The discharge module unit 31 is made up of parallel, laterally spaced side plates 32 and 33 which are approximately square. A front face plate 34 is affixed to corresponding edges of side plates 32 and 33 as by welding or by being an integral, bent portion of them. A top plate 35 is affixed to their adjacent edges preferably by welding. A curved plate 36 is attached along its curved edges to the side plates 32 and 33 and its curve is preferably a 90 arc. The straight edges of curved plate 36 are respectively attached to the face plate 34 and the top plate 35. All of these places of attachment are preferably gas tight.

The face plate 34 has a central hole 37 therein and it is surrounded by an internally directed, attached ring 38. The top plate 35 likewise has a central hole 39 therein and it is surrounded by an externally directed, attached ring 40. The top tube 23 lies within the face plate 34 and slidably fits the ring 38. A chimney or flue pipc (not shown) fits over the ring 40 of top plate 35. This discharge module unit 31, therefore, serves to direct incoming combustion gases from tube 23, upwardly into a chimney or flue. The tube 23 is a duplicate of tubes 21 and 22 since the discharge module unit 31 has the same depth as that of the reverse-flow module units 10. I

Each one of the modules 10, 10a, 10b, 26, and 31 is of an independent, unitary, firm, self-supporting construction such that it will withstand the stresses imposed by severe temperature changes, shipment, and storage when stacked on top of each other. Each one of them may be replaced by a duplicate without the need to discard either one of the other two types. The sheet metal screws 24 and 30 which attach the one end of the combustion tubes to its abutting module, are easily removed and replaced in the repaired assembly.

To hold the module units 10, 26, and 31 in their special relationship, two independent side frames 45 and 46 are provided. A description of the one will suffice for both of them as they are mirror images of each other. Referring to side frame 45 in FIG. 5, it is made up of so-called angle iron in that a cross section of it is a right angle. The frame 45 is made up of two spaced apart vertical bars 47 and 48 and two spaced apart horizontal bars 49 and 50. They are connected together at their meeting ends by rivets, bolts and nuts, sheet metal screws, by welding or any mechanical means so that a rigid, open oblong frame is formed. The angle bar members are so related to each other that their faces 47a, 48a, 49a, and 50a are flatwise and their faces 47b, 48b, 49b, and 50b all extend outwardly in the same direction to form a box-like, shallow, open, construction.

The reverse flow modules 10, 10a, and 10b and the discharge module 31 are attached to the faces 47a and 48a so that the modules are vertically spaced in proper position relative to one another. This attachment is preferably by sheet metal screws 51, bolts and nuts, or other means in anticipation of replacement needs. The side plates 12 and 33 of the modules are fastened to the faces 47a and 48a, while the side plates 11 and 32 of the modules are fastened to the corresponding faces (not numbered) of the other frame 46.

The burner receiving or attachment plate 27 is fastened by sheet metal screws 44 or other means to the face 48b of frame 45 and to the corresponding face (not numbered) of the other frame 46. This serves to direct the ring 29 inwardly of the heater structure so that it will receive combustion tube 20 thereover.

As the modules 10 and 31 and the burner module 26 are all of rigid, strong construction even though they are separate units, they serve to hold and support the frames 45 and 46 in spaced relation. There is no need, therefore, for any angle irons to tie the two frames 45 and 46 together as this is done by the module units themselves. As there is no complete, box-like frame, the two side frames 45 and 46 would be movable relative to each other if the modules were not present between and fastened to them.

The frames 45 and 46 also serve as a framework to support the side reflectors 52 and the end reflectors 53. This support is provided by the angle irons 54, 55, and 56 which are attached at their ends to the faces 49a and 50a; this attachment may be by means of any mechanical means mentioned above. The faces 54a, 55a, and 56a fit flatwise against the faces 49a and 50a so that the other faces (not numbered) of the angle irons extend away from the frame 45, opposite from the faces 49b and 50b. There are three vertical angle irons 54, 55, and 56 shown, but there could be more or fewer, depending on the strength of the reflectors 52 and on the overall length of the heater.

Attached to the angle irons, preferably by welding, are the supporting arms 57. Their ends 57a and 57b are bentin the same direction away from the middle portion, the end 57a being at an obtuse angle and the end 57b being at an acute angle. The end 57a is attached to the angle irons so that the acutely disposed end 57b projects upwardly so as to form a comer for the side reflectors 52 to abut against. The reflectors 52 remain in their assembled position by gravity alone and are easily removable to enable access to the tubes and module units.

The end reflectors 53 are attached to and are carried by the side reflectors 52. To accomplish this, each side reflector is provided at both ends with a tab 61 which is fastened by sheet metal screws 62 or alternative means to the adjoining ends of the end reflectors. This arrangement could be reversed by providing similar Some of the lower end reflectors at the burner end of the heater have been omitted as they would be in the way of the burner itself. In the arrangement of FIGS. 1-9, there are twelve vertically spaced reflectors except at the burner end where the lowermost four have been eliminated, but it is to be understood that there may be more or fewer reflectors as this is generally determined by their widths and desired spacing. The burner (not shown) is attached in place by bolts 66 fastened to plate 27 of the burner module unit and to shield the burner from the intense heat radiated from the adjacent combustion tubes and module unit 10, a shield plate 63 is provided where the end reflectors are not present. This shield plate 63 is vertically disposed but its upper portion is curved (see FIG. 4) so as to partially overlie the burner and afford it better heat protection.

The shield plate 63 can be attached by screws 64 to the outer face 48b of frame 45 and the corresponding face of frame 46. It must have a central opening large enough so that the burner can pass through it and fit firmly against the plate 27. The four lowermost side reflectors are made slightly shorter than the upper eight so that they terminate at the rear of the shield plate 63. These four lowermost side reflectors are formed with the same tabs 61, but they are bent at an angle so that they may be attached flatwise against the shield plate 63 by the same sheet metal screws 62 or alternative means.

To suspend the assembled heater from the ceiling or other superstructure, hanger bolts 67 will generally be used. They may be welded to opposite ends of the top face 49b of frame 45 and to the corresponding top face of the other frame member 46. Or, these hanger bolts 67 may pass through holes in these top frame members and be held in place by bolt heads or nuts on the undersidcs of the top frame members.

To prevent heat loss at the top of the heater a cover 69 is provided. It has a peripheral, descending flange to abut against the topmost side and end reflectors so as to hold the heat in. It may or may not, as desired, be screwed down against the topmost face 49b.

The assembly of the heater is facilitated by the use of the modular units of the invention and almost any order of securing the parts in place may be followed, having in mind that the tubes cannot be inserted if both of its end modules are fixed in place. One easy mode of assembly is to first attach the plate 27 of the burner module unit 26 to the face 48b of the vertical frame member 48 and to the corresponding vertical frame member of the other frame. This assembly will include the lower tube 20 which is held on ring 29 by screws 30 or alternative means. Next, the lowermost return flow module unit a is passed over the free end of tube and this module unit is fastened in place. Then, the tube 21 is secured to this same return flow module unit 10a and the opposite free end of tube 21 is located in its return flow module unit, after which this latter module unit 10 is secured in place. This procedure is repeated until the discharge module unit 31 is fastened in position. Finally, the reflectors 52 and 53 are located in place, shield 63 is attached, and cover 69 is applied.

If tube 21 becomes burned out, for instance, it is merely necessary to remove the reverse-flow module 6 unit 10 to which it is attached, without having to replace any other tube or module unit. Replacement of the tube 21 is then readily accomplished and all the original parts are retained. In similar manner, if the module unit 10a becomes burned out, it alone needs to be replaced without requiring replacement of module unit 10, 10b, or 31.

The feature of the invention, therefore, is the provision of the separately functional modular units; i.e., the burner receiving module, the reverse-flow module, and the discharge module which are not themselves connected together but which are supported in a seriesflow disposition by independent attachment to two side frames which otherwise are not connected together. It

is this novel arrangement which facilitates the assembly of the completed heater and which makes it easy to replace only the damaged functional module without having to discard any other functional module. This also makes it possible to sell as a distinct, separate product, each of the module units and to stockpile each kind apart from the others.

The modification of FIGS. 10 to 15 shows several variations or improved features over the structure of FIGS. 1 to 9 inclusive. A structure made according to FIGS. 10 to 15 would have the same construction (except possibly for the reflector vane supports) at its left end, as the left end of the heater of FIGS. 1 to 9. Or, stated differently, one or more or all of the features of FIGS. 10 to 15 may be incorporated in the heater of FIGS. 1 to 9.

One possible change from FIGS. 1 to 9 is the replacement of the reflector supporting angle irons or vertical bars 54, 55, and 56, with the reflector supporting plates 71, best shown in FIGS. 14 and 15. These plates 71 are preferably made of sheet metal and are bent at their long edges to form right angle flanges 72 and 73. The flange 72 is used to attach, as by sheet metal screws, the plates 71 to the top and bottom horizontal bars 49 and 50 of the two side frames 45 and 46. The flange 72 also serves to strengthen the plate 71 and the outer flange 73 provides additional strengthening.

Each plate 71 is perforated with the oblong, slanting cutouts or openings 74 to receive and support the side reflector vanes 52. These plates 71 may be made rapidly by a forming and stamping operation, and they have the feature of eliminating the many bent, supporting arms 57 and their individual attachment to the vertical bars 54, 55, and 56. The sheet plates 71 may replace one, several, or all of the bars 54, 55, and 56.

Another feature which is incorporated in FIGS. 10 to 15 is the floating support of the reverse-flow module 10 so that it can move back and forth relative to the other modules 100 and 10b. Thus, the module 10 can move away from modules 10a and 10b to accommodate the lengthwise expansion of tubes 21 and 22 under the influence of the combustion heat. When the tubes 21 and 22 cool off and contract in length, the module 10 can move back to its position for cooled conditions.

This is accomplished by eliminating the direct attachment of module 10 to the vertical end bar members 48 of the two side frames 45 and 46. To hold the module 10 in position, against an up and down movement, it fits between angular guide plates 75 which are attached to the sheet plates 71. These guide plates 75 are fastened to the flange 72 of each vertical plate 71 and project inwardly so that the module 10 loosely fits between them as is best shown in FIG. 14.

If the vertical bars 56 of FIG. are present instead of the plates 71 of FIG. 14, the angular guide plates 75 would be attached to the bars 56. Movement of the module 10 sidewise out of the frame is prevented by the faces 48a (see FIGS. 5 and 11) as the module 10 loosely fits between them. As is stated above, the module 10'is not firmly fixed in position but is supported in a floating manner so that it can move back and forth within the up and down restraints of guides 75 and the sidewise restraints of faces 48a.

To simplify the construction, the discharge module unit 31 may be replaced by discharge module unit 76 which is simply a plate with a hole in it for the upper tube 77 to pass through. The tube 77 is longer than tube 23 which it replaces, as the exhaust module 31 is not present and the tube 77 must be long enough to pass through the exhaust module unit 76. A straight exhaust flue pipe can be engaged over the projecting end of tube 77 to carry the exhaust gases to and through a side wall of a building. Or, a flue pipe elbow can be engaged over the projecting end of tube 77 so that the exhaust gases can be conducted up and out of the roof.

The plate 76 constitutes a module unit in the sense that it is used here as it is fastened to the vertical end bar members 48 of both side frames 45 and 46 to sup port them in spaced relationship, and the plate 76 also serves to support the adjacent end of tube 77. The module unit 76 therefore serves a dual function such as is served by the module unit 31 which it replaces.

If the long tube 77 is utilized, the upper three or four of the end reflector vanes 53, shown at the right hand end of FIG. 1, must be eliminated. The side reflector vanes 52 which would have been connected to these removed end vanes 53 will be connected to the plate 76 and the plate 76 should be long enough to permit this.

In FIG. 4 the lower tube fits over or around the outside of the cylindrical ring 29 of the burner receiving module unit 26, whereas in FIGS. 10 to 13 the lower tube 20 fits within a larger cylindrical ring or collar 80. The tube 20 can move back and forth therein when the tube expands and contracts during its heating and cooling. The collar 80 has a flat base 81 welded 0r integral therewith so that the collar 80 and base 81 are cup shaped. The burner attachment bolts 66 are welded to the flat base 81. The base 81 has a central hole therein for the burner flame to pass through. The bolts 66 pass through holes in a supporting plate 82 and this plate is attached as by sheet metal screws 83 to the end vertical bar members 48 of the side frames 45 and 46. This holds the cup shaped member 80-81 in fixed position, and the elements 82, 80, and 81 thereby constitute a burner supporting module which serves the function of module 26 in FIG. 9. The heat shield 84 (similar to 63) has holes therein for the bolts 66 to pass through and this supports the shield 84. When a burner is attached to the bolts 66, the cup shaped member 80-81, the supporting plate 82, and the heat shield are all clamped together and the central holes in them should all align up.

When tube 20 is cool or at room temperature, it should be short enough so that its end is spaced from the base plate 81 as is shown by the space at 85. This space or gap should be so large that when tube 20 is hot because of the flame being projected into it, the expansion of the tube 20 will just about close this gap. The

8 end of tube 20 should not press forcibly against the base plate 81 as this could press the frames out of shape or cause other permanent distortion.

In FIG. 12 is shovm a burner gasket 86 of a heat resistant substance of conventional construction and material. Its end outside face at 87 should be flush with the end of tube 20 as shown in FIG. 12. This gasket 86 should forcibly fit in tube 20 so'that it moves with the tube and cannot be dislodged except by manual pressure. When the tube 20 expands, the end face 87 should snugly press against the face of base plate 81 so that a substantially gas tight seal is formed.

To assemble the structure of FIGS. 10 to 15, substantially the same order is followed which has been explained for the heater of FIGS. 1 to 9 inclusive, however, with the slip fit between the lower tube 20 and the collar 80, this lower tube should be attached to the module unit 10a. In like manner, tube 21 is attached to the'module 10 by a long self tapping screw 90 which passes through the side plate 12 of this module,through its ring 16 and through the end of the tube 21. A similar long self tapping screw passes through plate 1 1 of module 10 and through the diametrically opposite side of ring 16 and tube 21. This same attachment is provided between the tube 22 and the module 10b.

In the heater of P16. 10, therefor, the end of tube 20 within collar 80 can move back and forth therein, the end of tube 77 within plate 76 can move back and forth therein, and the other ends of the tubes are attached to the return-flow modules 10, 10a and 10b. The structural details, and the back and forth movability of module 10, accommodates the expansion due to heat.

FIG. 12 shows the preferred structure in which the collar 80 is integral with the base 81 but if desired the collar can be a separate cylinder which is attached as by welding to the base plate 81. Or, if the collar is a separate cylinder it can be welded to the plate 82 which is attached to the flanges 48b of the two vertical bars at the same end of the heater. This plate 82, like plate 76, serves to fixedly space the frames at this end of the heater.

FIG. 14 shows the guides attached to the slotted vertical plates 71 and it shows the plates 71 about midway of the width of the module 10 so that the module is balanced on the guides. This is preferred but the guides 75 could be attached to the vertical frame bars 48.

The gasket 86 is shown as a lining within the end of tube 20 and it preferably has integral therewith the disc portion 88 which is centrally apertured for the combustion flame to pass through. The increased surface provided by this apertured disc portion 88, to bear against the plate 81, serves to establish a better gasket seal when the expansion of the tube brings them into contact. This apertured disc portion 88 can lie partially beyond the end of tube 20 as it is supported by the lining portion 86.

The lining 86 protects the tube against the intense heat of the burner flame and it is made of asbestos or asbestos like material. It is sold as a corbel unit and as a pyrolite combustion chamber.

As has been stated above, various combinations of the structural details of FIGS. 1 to 9 inclusive may be combined or interchanged with the structural details of FIGS. 10 to 15 inclusive. For instance, the top tube 77 and module unit 76 may be substituted for the top tube 23 and module unit 31. Or, the structural details of FIG. 12 can replace the structural details of FIG. 4. In like manner, the return-flow module in FIG. 1 can be supported in a floating manner as is shown in FIG. 11.

What is claimed is:

l. A space heater which delivers radiant heat downwardly which comprises a separately functional burner receiving module unit, a series of separately functional reverse-flow module units, a separately functional discharge module unit, two side frames each made up of two horizontal bar members and two vertical bar members connected at their meeting ends to form an open frame, and combustion tubes disposed parallel to said side frames and arranged to direct combustion gases from the burner receiving module unit, through the reverse flow module units and finally through the discharge module unit, said combustion tubes being connected to and supported by said module units, and several of said module units being attached to said vertical bar members to thereby hold and support said two side frames in their spaced relationship.

2. The space heater according to claim 1 in which all of the module units are connected to said vertical bar members.

3. The space heater according to claim 1 in which the burner receiving module and the discharge module units are connected to the same end vertical bar members and the reverse-flow module unit between these latter module units is supported for free endwise movement.

4. The space heater according to claim 1 in which the discharge module unit is a plate which is attached to vertical bar members at the same end of the heater and it has a hole therethrough to receive and support a combustion tube.

5. The space heater according to claim 1 in which the discharge module unit includes two spaced side plates which are connected respectively to the two vertical bar members at the same end of the heater and also includes a curved plate which is attached to said two spaced side plates and serves to direct the gases through a guarter turn.

6. The space heater according to claim 1 in which the reverse-flow module units each include two spaced side plates and a curved plate attached to them and serving to direct the gases through a half turn, the side plates of at least one of the reverse-flow module units being connected respectively to the two vertical bar members at the same end of the heater.

7. The space heater according to claim 1 in which the burner receiving module unit includes a plate and a collar projecting therefrom inwardly of the heater, the end of the associated combustion tube having a sliding fit within said collar, and a heat resistant material lines the interior of said tube end and serves as a gasket by contact with said plate upon lengthwise heat expansion of the tube.

8. The space heater according to claim 7 in which said heat resistant'material includes an apertured disc portion which provides an increased gasket surface to contact said plate and form a sea]. I

9. The space heater according to claim 1 in which the burner receiving module unit includes a plate which is attached to vertical bar members at the same end of the heater and it has a hole therethrough for the passage of a combustion flame.

10. The space heater according to claim 1 in which slotted vertical plates extend between and are attached to the horizontal bars of each frame and horizontal reflector vanes are carried in the slots.

11. A space heater which delivers radiant heat downwardly which comprises a separately functional burner receiving module unit, a series of separately functional reverse-flow module units, a separately functional discharge module unit, two side frames each made up of two horizontal bar members and two vertical bar members connected at their meeting ends to form an open frame, and combustion tubes disposed parallel to said side frames and arranged to direct combustion gases from the burner receiving module unit, through the reverse-flow module units and finally through the discharge module unit, said module units being connected to the combustion tubes and being attached to said vertical bar members so that the module units serve the dual functions of supporting the combustion tubes in said relationship and also holding and supporting said two side frames in their spaced relationship.

12. The space heater of claim 11 in which at least one of said reverse-flow module units includes two spaced side plates which are attached respectively to said side frames. 

1. A space heater which delivers radiant heat downwardly which comprises a separately functional burner receiving module unit, a series of separately functional reverse-flow module units, a separately functional discharge module unit, two side frames each made up of two horizontal bar members and two vertical bar members connected at their meeting ends to form an open frame, and combustion tubes disposed parallel to said side frames and arranged to direct combustion gases from the burner receiving module unit, through the reverse flow module units and finally through the discharge module unit, said combustion tubes being connected to and supported by said module units, and several of said module units being attached to said vertical bar members to thereby hold and support said two side frames in their spaced relationship.
 2. The space heater according to claim 1 in which all of the module units are connected to said vertical bar members.
 3. The space heater according to claim 1 in which the burner receiving module and the discharge module units are connected to the same end vertical bar members and the reverse-flow module unit between these latter module units is supported for free endwise movement.
 4. The space heater according to claim 1 in which the discharge module unit is a plate which is attached to vertical bar members at the same end of the heater and it has a hole therethrough to receive and support a combustion tube.
 5. The space heater according to claim 1 in which the discharge module unit includes two spaced side plates which are connected respectively to the two vertical bar members at the same end of the heater and also includes a curved plate which is attached to said two spaced side plates and serves to direct the gases through a guarter turn.
 6. The space heater according to claim 1 in which the reverse-flow module units each include two spaced side plates and a curved plate attached to them and serving to direct the gases through a half turn, the side plates of at least one of the reverse-flow module units being connected respectively to the two vertical bar members at the same end of the heater.
 7. The space heater according to claim 1 in which the burner receiving module unit includes a plate and a collar projecting therefrom inwardly of the heater, the end of the associated combustion tube having a sliding fit within said collar, and a heat resistant material lines the interior of said tube end and serves as a gasket by contact with said plate upon lengthwise heat expansion of the tube.
 8. The spaCe heater according to claim 7 in which said heat resistant material includes an apertured disc portion which provides an increased gasket surface to contact said plate and form a seal.
 9. The space heater according to claim 1 in which the burner receiving module unit includes a plate which is attached to vertical bar members at the same end of the heater and it has a hole therethrough for the passage of a combustion flame.
 10. The space heater according to claim 1 in which slotted vertical plates extend between and are attached to the horizontal bars of each frame and horizontal reflector vanes are carried in the slots.
 11. A space heater which delivers radiant heat downwardly which comprises a separately functional burner receiving module unit, a series of separately functional reverse-flow module units, a separately functional discharge module unit, two side frames each made up of two horizontal bar members and two vertical bar members connected at their meeting ends to form an open frame, and combustion tubes disposed parallel to said side frames and arranged to direct combustion gases from the burner receiving module unit, through the reverse-flow module units and finally through the discharge module unit, said module units being connected to the combustion tubes and being attached to said vertical bar members so that the module units serve the dual functions of supporting the combustion tubes in said relationship and also holding and supporting said two side frames in their spaced relationship.
 12. The space heater of claim 11 in which at least one of said reverse-flow module units includes two spaced side plates which are attached respectively to said side frames. 